Studies on phagocytosis of mucoid and nonmucoid variants of Pseudomonas aeruginosa. II. Induction of heterologous immunity by mucoid strains of P. aeruginosa

Abstract

The studies were performed to determine the level of phagocytosis and intracellular killing of mucoid P. aeruginosa strains in normal and monovalent immune sera against: mucoid (anti-OM) and nonmucoid (anti-O) variants and slime extracts (anti-M) of 15 P. aeruginosa strains belonging to 7 immunotypes of Fisher's scheme. Extracellular P. aeruginosa slime was observed to inhibit the process of phagocytosis and intracellular killing of these bacteria. On the other hand, antibodies directed against the extracellular slime neutralized the inhibitory effect of the slime on phagocytosis. Slime of strains of different somatic antigen displayed serological affinity. This was due to cross reactions in phagocytic and agglutination test of mucoid strains in immune sera containing anti-slime antibodies. Strains of the same somatic antigen produced antigenically differentiated slime.